A Convenient Synthesis of Substituted 1-Bromo-1-nitroalkenes
作者:Yanchang Shen、Baozhen Yang
DOI:10.1080/00397919308020394
日期:1993.1
Abstract The reaction of aldehydes with bromonitromethane in the presence of tri-n-butylarsine affording substituted 1-bromo-1-nitroalkenes in good yields is described.
Asymmetricorganocatalyticdomino type Michael-SN2 reactions give access to enantiomerically enriched dihydrofuran derivatives that can be used as valuable chiral building blocks. A variety of α-bromonitroalkenes and 1,3-dicarbonyl compounds were allowed to react under optimized conditions, in the presence of a bifunctional quinine-derived sterically encumbered squaramide (H-bond donor) organocatalyst
不对称有机催化多米诺骨牌型 Michael-S N 2 反应提供了对映异构富集的二氢呋喃衍生物,可用作有价值的手性构件。在双功能奎宁衍生的空间位阻方酸酰胺(H 键供体)有机催化剂的存在下,允许各种 α-溴硝基烯烃和 1,3-二羰基化合物在优化条件下反应。本文中开发的条件在反应持续时间(1-6 小时vs. 24-96 小时)和反应温度(室温vs. -20 °C 至 -50 °C )方面优于文献中已知的方法) 产生具有高达 97% ee 的良好对映选择性的非对映选择性产物。
Asymmetric Synthesis of Dihydrofurans via Organocatalytic Domino Michael-Alkylation Reaction
organocatalyst to catalyze the asymmetric domino Michael–alkylation reaction between cyclohexane‐1,3‐dione derivatives and bromonitrostyrenes. For dimedone, the corresponding bicyclic 2,3‐dihydrofurans with two stereocenters were obtained in up to 99 % yield with 95:5 d.r. and 96 % ee. For prochiral 5‐monosubstituted cyclohexane‐1,3‐diones, the desymmetrization reaction provided the bicyclic 2,3‐dihydrofurans
作者:Fei-Yu Chen、Li Xiang、Gu Zhan、Hong Liu、Bin Kang、Shu-Cang Zhang、Cheng Peng、Bo Han
DOI:10.1016/j.tetlet.2020.151806
日期:2020.4
The highly stereoselective synthesis of pyrrolidine-fused spirooxindole derivatives bearing a carbon-halogen bond and contiguous quaternary carbon stereocenters was achieved via a [3+2] cycloaddition reaction. This method provided facile access to a collection of enantiomerically pure spiro[pyrrolidin-3,2’-oxindoles] containing halogenated contiguous quaternary carbon stereocenters in good to high
通过[3 + 2]环加成反应实现了具有碳-卤素键和连续的季碳立体中心的吡咯烷稠合的螺并氧杂吲哚衍生物的高度立体选择性合成。该方法可轻松获得对映体纯的螺[吡咯烷-3,2'-羟吲哚]的集合,其中包含卤化连续的季碳立体中心,具有良好至高产率(48-84%)和出色的立体选择性(高达> 20:1 dr和> 99%ee)。可以通过亲核取代(S N 2)反应将含卤素的产物立体选择性地转化为硫化衍生物,这表明它们可以作为具有潜在生物活性的共价抑制剂的开发候选者。